A conventional mobile terminal apparatus has a communications function of connecting to a wireless local area network (LAN). The mobile terminal apparatus, for example, can connect to a network, such as the Internet, through wireless LAN access points provided in various areas.
A related technique, for example, compares a threshold and the SNR value generated based on a beacon frame signal received from a nearby AP, classifies the nearby AP as a detection AP, a candidate AP, or a target AP, and based on the classification, determines an AP for performing handover. Further, according to another technique, a mobile terminal transmits a probe request frame to plural base stations and receives a probe response frame from each base station, whereby the mobile terminal uses the reception level of the probe response frame as a reference and determines the next base station for handover.
According to another technique, a wireless LAN terminal apparatus judges the necessity of handover based on base station information of a detected base station and a first base station with which the wireless LAN terminal apparatus is currently associated. If handover is necessary, the wireless LAN terminal apparatus determines a second base station from among base stations and associates the wireless LAN terminal apparatus with the second base station. According to yet another technique, when response messages received from connectable relay apparatuses do not include information coinciding with the apparatus identification information of the connected relay apparatus, the communications apparatus requests connection to a relay apparatus whose apparatus identification information is included in a received response message.
According to another technique, a wireless LAN mobile station measures the communication quality of information communicated with a wireless LAN base station and upon judging that the measured communication quality is less than a given communication quality, the wireless LAN mobile station increases by a given value, a threshold serving as a reference for executing handover. According to yet another technique, a wireless LAN mobile station counts the number of times handover is executed per unit time and according to the counted number of executions, varies a threshold that serves as a reference for executing handover. According to a further technique, a wireless LAN terminal connected to a wireless access point supplies from a key information registry (KIR), a communications parameter of a nearby wireless access point before roaming to a second wireless access point near the wireless access point actually becomes necessary.
For examples of such conventional techniques refer to Japanese Laid-Open Patent Publication Nos. 2005-333648, 2007-166412, 2008-131069, 2010-021765, 2007-251652, 2007-251654, and 2004-241937.
Nonetheless, with the conventional techniques above, a problem arises in that scanning operations to search for the next access point for handover when the reception signal strength of a signal received from the connected access point drops invites increases in the power consumption of the mobile terminal apparatus.